Carefully cut the spaghetti squash in half lengthwise. Scrape out the seeds and strings, taking care not to cut too deeply into the smooth flesh (which will become the sought-after strands of spaghetti squash after it is cooked!).
Place the rack in the bottom of the Instant Pot and pour in one cup of water or broth.
Place the cut and scraped spaghetti squash halves on the rack, nestling them in so they fit well below the top of the pot. Secure the lid and make sure the valve is pointing up to "sealing" and not down toward "venting."
Select Manual. Then dial up or down using the - or + buttons to get to 7 minutes (this is for ultra-tender squash; if you like it a bit more toothsome, decrease the time to 5 minutes).
The Instant Pot will start doing it's thing - first showing ON and then counting down the time once pressure is reached.
Once the Instant Pot beeps to signal end of cooking time, hit Cancel.
Quick release the pressure by using a long-handled spoon or other device to flip the knob down to "venting." Steam will rush out until the pressure is released, the silver float valve will drop, and you can safely open the Instant Pot.
The squash will be piping hot. Using tongs or a fork jabbed into the side of the squash, remove the squash to a cutting board. Let it cool a bit (or not) and then scrape the tender squash away from the sides to form a jumble of spaghetti squash strands (you can scoop it entirely out of the "shell" into a tupperware or other container and use immediately or refrigerate for up to a week).